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Vintage Telephony and Telecomms Vintage Telephones, Telephony and Telecomms Equipment |
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8th Mar 2019, 5:16 pm | #21 |
Dekatron
Join Date: Nov 2003
Location: Heckmondwike, West Yorkshire, UK.
Posts: 9,642
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Re: External telephone line junction box.
It would seem to depend on the difference between a fault and damage once the line enters your property, not necessarily at the master socket. Post 1 would have been chargeable: http://bt.custhelp.com/app/answers/d...ervice-charges
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8th Mar 2019, 8:38 pm | #22 |
Triode
Join Date: Nov 2016
Location: Frinton on Sea, Essex, UK.
Posts: 45
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Re: External telephone line junction box.
I remember going on the 10ft poles to do the open wire tensioning training freezing day in December with white frost on the poles and wires, also the aerial joint to drop wire on full hight poles in a large metal building. I think it was the apprentice A course.
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8th Mar 2019, 11:54 pm | #23 |
Nonode
Join Date: Oct 2014
Location: West Midlands, UK.
Posts: 2,181
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Re: External telephone line junction box.
Graham, you conjure up visions of open wire to house ( AKA Subs premises) , with insulators 16 ( from memory ) fitted on the house, to allow for the open wire to be joined to a flat copper wire leader to the "protector" ( with line fuses & carbon protectors, fitted with a protective earth) . Most dropwire in this era were copper coated cadmium or steel. But for those thinking of using what is known as "jelly crimps", I know from experience and old anecdotal evidence from old maintenance contacts that what happens with these is that the connection remains protected, but corrosion forms on the outer of the crimp and HR occur. Saying that I've come across many a Krone strip hidden in /under lead cladding where there's been no problems with damp.
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9th Mar 2019, 10:13 pm | #24 |
Dekatron
Join Date: May 2010
Location: Greater Manchester, UK.
Posts: 18,724
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Re: External telephone line junction box.
I didn't know that open-wire pairs were made of cadmium.
I do occasionally see bits of it in rural areas, and it's not inconceivable that some may still be in use on private land. How much of a danger did it pose to those who worked with it?
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9th Mar 2019, 10:24 pm | #25 |
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Re: External telephone line junction box.
"Copper" as used for catenary wire etc. is actually an alloy of copper and cadmium. Pure cadmium is not used.
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10th Mar 2019, 12:18 am | #26 |
Nonode
Join Date: Oct 2014
Location: West Midlands, UK.
Posts: 2,181
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Re: External telephone line junction box.
in my day- open wire was copper, but dropwire could be either copper coated steel or cadmium. Coper to give the transmission qualities, and a steel/cadmium inner to give strength. It's almost like the transmission properties of a co ax cable. Modern day drop wire has a two pair copper system, with steel cateniary supporting the drop wire.
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10th Mar 2019, 12:36 am | #27 |
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Re: External telephone line junction box.
Open wire was always a cadmium copper (cc) alloy rather than pure copper. It's much springier than pure copper and doesn't work harden and break so easily.
The use of copper coated cadmium for drop wire would have been prohititedly expensive as well as unnecessary. The comparison with a coaxial cable is invalid. A coaxial cable has two conductors, not one. I think you're referring to skin effect.
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10th Mar 2019, 12:53 am | #28 |
Dekatron
Join Date: May 2008
Location: Derby, UK.
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Re: External telephone line junction box.
When BT had to replace my old drop wire, the new stuff they used had four copper cores (white, orange, green and black) and three steel cores (all yellow). It was vandalised one night (together with everyone else's phone and TV cables; some must have gone along the whole street with a sharp knife) and subsequently repaired with gel-filled crimps inside a clip-together housing.
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10th Mar 2019, 3:26 pm | #29 |
Tetrode
Join Date: Dec 2012
Location: Andover, Hampshire, UK.
Posts: 85
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Re: External telephone line junction box.
Graham,
What type of cable was used to connect from the drop wire to the terminal block in the premises ? I seem to remember twin core copper, rubber sheathed and cotton covered. John |
10th Mar 2019, 4:01 pm | #30 |
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Re: External telephone line junction box.
The grey drop wire I remember was generally taken right into the premises and terminated directly on the terminal block just inside the door or window frame. Often the telephone line cord was terminated on the same terminal block.
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10th Mar 2019, 4:39 pm | #31 |
Tetrode
Join Date: Dec 2012
Location: Andover, Hampshire, UK.
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Re: External telephone line junction box.
Possibly I'm thinking of an earlier time - around the 1950's.
John |
10th Mar 2019, 5:35 pm | #32 |
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Re: External telephone line junction box.
ISTR there was an earlier drop wire coloured black. Possibly it was terminated on an old style protector. Or may be 2 core flat cable was run from the drop wire to the protector. If so I don't know how the connection was made, perhaps inside an old style insulator? The whole idea of drop wire was to get rid of insulators etc. The drop wire was mechanically terminated at the pole and premises using clamps. The later ones were coarse helixes of insulated steel wire which the drop wire was wound around. The earlier versions had some kind of sliding clamp.
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13th Mar 2019, 11:09 pm | #33 |
Heptode
Join Date: Jul 2007
Location: Flintshire, UK.
Posts: 707
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Re: External telephone line junction box.
Dropwire was introduced in early 1930's and used a small eccentric wheel known in the 'Vocabulary of Engineering Stores' as 'Clamps, Eccentric' for some reason They can still be seen around if you look ! This is a twin wheel version
but most were a single wheel. See Herbert & Proctors 'Telephony' Volume 1 pages 1159/60 The cable was one pair with cadmium copper conductors known as 'Cable, I.R.V., Braided and Compounded' - (IRV = India Rubber Vulcanised) Three types - Black, Grey or 'PBJ'. Only the PBJ was still in use with a sliding copper clamp with a loop around an inch across which was dropped over a spindle when I started with the GPO as a YIT in the 1950's. |
13th Mar 2019, 11:16 pm | #34 |
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Re: External telephone line junction box.
Thanks for that Pellseinydd.
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13th Mar 2019, 11:27 pm | #35 |
Heptode
Join Date: Jul 2007
Location: Flintshire, UK.
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Re: External telephone line junction box.
One of the junction boxes used for dropwire to internal cable is the 'Block Terminal No 16A' in grey or black, about 5cm square with no terminals - just room to house the crimped joints of the conductors. No terminals inside.
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19th Mar 2019, 4:15 pm | #36 |
Pentode
Join Date: May 2006
Location: Poole, Dorset, UK.
Posts: 130
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Re: External telephone line junction box.
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23rd Mar 2019, 9:48 am | #37 |
Hexode
Join Date: Jun 2011
Location: Glossop, Derbyshire, UK.
Posts: 487
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Re: External telephone line junction box.
Hi John glad the gel box con arrived the is the roundtoit you need as well
Dave
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23rd Mar 2019, 10:04 pm | #38 |
Triode
Join Date: Nov 2016
Location: Frinton on Sea, Essex, UK.
Posts: 45
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Re: External telephone line junction box.
The standard grey drop wire was called drop wire 3, the thicker black was drop wire 4 same conductors but thicker insulation , used when the run ran through trees to give better protection from the branches rubbing against it.
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24th Mar 2019, 1:37 am | #39 | |
Nonode
Join Date: Oct 2014
Location: West Midlands, UK.
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Re: External telephone line junction box.
Quote:
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27th Mar 2019, 7:28 pm | #40 |
Pentode
Join Date: Jan 2019
Location: Manchester, UK.
Posts: 163
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Re: External telephone line junction box.
I remember the steel cored dropwire being substantial stuff when I was an apprentice on overhead maintenance, I was barely strong enough to cut it with the cutters I had, and as 'the youth' I was left to tidy up any recovered wire, this was no mean task as it had a mind of its own and did not want to be coiled up.
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